[Sustained-action oral theophylline in the asthmatic child. Clinical, pharmacokinetic and respiratory function...

Twenty children aged between 5 and 16 suffering from severe asthma were treated with long acting oral theophylline. The minimum duration of treatment was three months and the maximum 12 months. Clinical, pharmacokinetic and pulmonary function studies were made. With a mean dose of 8.75 mg/kg, morning and evening, the theophylline blood levels on the 4th day of treatment (4 hours after the morning dose) were 12.3 +/- 4.36 mg/l. Those taken 4 hours after the evening dose 9.41 +/- 3.75 mg/l, suggesting a circadian rhythm for theophylline blood levels. The importance if fever is stressed in relationship to blood levels, which were increased by 67-100% with fevers of 38.5-39 degrees C. Treatment was very beneficial in 53% of cases. Respiratory function studies were performed in 13 children. After 4 days of treatment there was a significant decrease in airflow obstruction and hypoxemia However, despite carefully adjusted treatment, functional disturbances persisted, in particular hyperinflation.